1. Technical Field
The present invention relates generally to a covered welt for covering edges of an opening of a vehicle for example.
2. Background Art
A covered welt which is typically attached to an inner peripheral edge of an opening of a vehicle to be sealed by such as a closed door, for example, is well known in the art. Such a covered welt is usually formed with a U-shaped portion in the cross section thereof including a plurality of inner lips which are integrally formed on inner surfaces of side walls of the U-shaped portion, a curved cover lip which extends outwardly from the side wall of the U-shaped portion for receiving a distal portion of a roof garnish, and a C-shaped sponge rubber seal which is attached to the other side wall. The U-shaped portion wraps a flange which is bonded to an inner panel and an outer panel of a roof side rail of a vehicle body with tight engagement of the inner lips with the flange. The C-shaped sponge rubber seal is elastically deformable against shock caused by inner peripheral edges of a door when being closed. Fabric is attached over an outer surface ranging from an end of the sponge rubber to an end of the curved cover lip in a manner by which it is bonded by a pre-applied adhesive which is disposed all over the outer surface.
As an adhesive, two-part adhesives containing heat resistant curing agents or a hot-melt adhesives, for example, are typically used.
However, bonding of the fabric on the sponge rubber seal using a two-part adhesive or a hot-melt adhesive requires that the fabric remain pushed against the surface of the sponge rubber seal until the adhesive is hardened, due to lack of coking properties and lack of sufficient adhesion between the fabric and the rubber surface at the beginning of bonding. This results in complicated bonding operations and serious operational efficiency problems.
Additionally, a two-part adhesive must be bonded within a curing time (pot life) during reaction of the two adhesives because the adhesive strength soon disappears due to curing after mixing the two agents of the adhesive. Control of pot life is difficult and results in complicated bonding operations.
Hot-melt adhesives become extremely hardened after attachment to the fabric with the result that the fabric is tightly attached to the U-shaped portion and the sponge rubber seal, thereby preventing relative movement therebetween. For this reason, if the U-shaped portion is bent along an edge of an opening of a vehicle when it is installed, the fabric does not follow the bend, causing tensile force to occur. It will be thus noted that separation between the fabric and the curved cover lip tends to be generated, resulting in difficult installation. Further, an elastic reaction of the sponge rubber seal caused by the hardening of the adhesive results in excessive elasticity and thereby, poor sealing for doors, windows, etc.